JPH01173979A - Picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To successively obtain a picture searching at a high speed with a quick feeding mode by dividing a picture element signal equivalent to one picture into plural sub-picture signals sub-sampled in units of sub-pictures and successively arranging the plural sub-picture signals on a track. CONSTITUTION:Each unit block to compose a complete one picture 100 is made into one picture element, and a recording is executed so that all the picture elements are sub-sampled for 1/2 respectively in a length (vertical direction) and a width (horizontal direction), divided into four sub-pictures, and successively arranged between a guarding band tracks 201 and 201 by making the sub-picture into one unit. In the case of the quick feeding mode, for example, only the signal of the first sub-picture, which comes immediately after the guard band 201, is read and reproduced, and the signal recording parts of from a second sub-picture to a fourth sub-picture are skipped. Further, when the signal of the first sub-picture is lacking, the lacking part is detected using error detecting information and is supplied with the signal of the second sub-picture. Thus, the picture searching can be obtained successively at a high speed with the quick feeding mode, and further, a noise never occurs in a picture even when any lack exists in the information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image recording and reproducing apparatus that digitizes image information and records and reproduces it on a recording medium (magnetic tape, floppy disk, etc.).

(Prior Art) Devices for recording and reproducing still images on magnetic tapes and floppy disks have been known.

Since this device modulates the signal to be recorded and records it on the recording medium in an analog manner, there are limits to maintaining information quality such as deterioration of image quality.

On the other hand, as a method for solving the above problem, a method is known in which image information is digitally encoded and recorded on a recording medium. However, although this method can standardize information quality by digitizing it, there is a problem in that it takes more time than the conventional method to record and reproduce information of sufficiently high quality (for example, 400,000 pixels). This is because there are limits to the amount of information and information speed of the recording/reproducing system. for example,
If one pixel is represented by 8 bits, 400,000 pixels is 3.
If the information speed is 2 Mbit and the information speed is 1.55 M bps, 2.07 seconds are required to record or reproduce one screen. Such a time-consuming recording or reproducing device is inconvenient when searching for a desired screen by searching screens one after another as if searching through a book quickly (hereinafter referred to as fast-search mode).

Further, in the case of a conventional analog recording method or a digital recording method in which information is recorded in the order of transfer, there is a problem in that noise occurs on the screen when a part of the information is lost.

(Problems to be Solved by the Invention) As mentioned above, the conventional recording and reproducing method has the problem that it takes time to search for a desired image in fast forward mode, and when information is missing, noise appears on the screen and the image quality is poor. The problem is that it damages the

Therefore, by devising the distribution of image signals and the recording format, this invention makes it possible to quickly obtain a screen search remotely in sequence at high speed, and also effectively compensates for any missing information and eliminates noise in the image. It is an object of the present invention to provide an image recording and reproducing device that does not cause this problem.

[Structure of the Invention] (Means for Solving the Problems) This invention divides a pixel signal for one screen into a plurality of sub-screen signals obtained by subsampling them, and sequentially arranges these sub-screen signals in respective tracks. It was designed so that it could be recorded.

(Function) By the above means, the information for one screen is divided into multiple sub-screens and arranged, so you can quickly play back only the representative sub-screen signal remotely, which saves time. Furthermore, information loss can be compensated for using related sub-screen signals.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of this invention, and FIGS. 2 to 4 are diagrams shown for explaining the invention in detail.

First, in order to facilitate understanding of the invention, explanation will be given from FIG. 2. For example, the portion indicated by the reference numeral 100 in FIG. 2 is a complete digital screen, and each unit block constituting the complete screen 100 is one pixel. Here, all pixels are vertically arranged.

It is assumed that sub-sampling is performed by 1/2 in the horizontal direction and the image is divided into four sub-screens. In other words, a first sub-screen consisting of pixel groups according to ■, a second sub-screen consisting of pixel groups according to ■, a third sub-screen consisting of pixel groups according to ■, and pixels according to ■ A fourth sub-screen consisting of groups is created.

When these first to fourth sub-screen signals are recorded by the helical scan method, they are recorded so that they are sequentially arranged between guard band tracks 201 and 201, with each sub-screen as one unit, as shown in FIG. Ru. As the guard band track 201, a predetermined detection code record or no signal is used.

Therefore, as described above, if you want to reproduce one complete screen by reproducing the tape 200 on which image signals are distributed and recorded, all the signals of the first to fourth sub-screens will be reproduced, and as shown in FIG. The image will be reconstructed and projected as shown in .

However, if you are remote early, for example, Gartband 2
By reading and reproducing only the signal of the first sub-screen that comes after 01 and skipping the signal recording portions of the second to fourth sub-screens, it is possible to search for the contents of the desired screen at high speed.

In this case, in the playback screen, the signal of the first sub-screen is used over the entire screen as shown in FIG. 4, so although the image quality itself becomes coarse, this does not interfere with the purpose of the search.

In the above example, only the first sub-screen signal is picked up, but the second sub-screen is also picked up, and if part or all of the first sub-screen signal is missing, that part is picked up. , it is possible to eliminate image noise by detecting it using error detection information and supplementing it with the signal of the second sub-screen.

Furthermore, if you try to display a high-quality image in normal playback using all of the signals from the first to fourth sub-screens, and if the signal from the third sub-screen is missing, then as shown in Figure 5. As shown in the figure, at the position of the signal ■ on the third sub-screen, this 13
The signal ■ of the first sub-screen, which is similar to the number, can be substituted. Therefore, a reproduced image can be obtained without producing large noise. The third sub-screen signal may be lost if the tape is scratched or bent, or if dust is temporarily attached to the head.

FIG. 1 shows an example of a system for realizing image recording and reproduction as described above.

For example, an NTSC analog video signal is supplied to the input terminal 1 and introduced into the analog-to-digital converter 2 . The digitized image information is separated into brightness information and color information in a brightness/color separator 3, subjected to predetermined signal processing, and then synthesized again in a predetermined format. It is stored in the frame memory 12.

In the frame memory 12, write addresses and read addresses are designated by addresses from the frame memory address generation section 11. The data for one screen written in the frame memory 12 is supplied to the modulator 8 via the bus 5, the buffer amplifier 6, and the digital-to-analog converter 7, where it is converted into the original video signal and sent to the output terminal 9 for monitoring. is derived.

Further, data for one screen written in the frame memory 12 is transferred to the memory 16 via the bus 5, buffer amplifier 13, and bus 15. The memory 16 is subjected to sub-sample read control as explained in FIG. 2 under address control by the memory address generator 18. As a result, the first to fourth sub-screen signals are sequentially read out from the memory 16 and supplied to the signal recording/reproducing section 24 via the bus 15. In this signal processing, data from one header generator is used once in the middle of a complete one-screen signal and is used to form the guard band track 201 shown in FIG.

The recording signal outputted from the signal recording and reproducing section 24 is further added with an error detection and correction code by the error detection and correction section 25, and is supplied to the rotary head 40, 40 attached to the drum 36 of the rotary head device. This allows the third
A record in the format explained in the figure is obtained.

The rotating head device and its surroundings will be explained.

Between the supply reel 35 and the pick-up reel 38,
Tape 3 passes through drum 36 and capstan 37.
9 is passed. Supply reel 35, drum 36. Capstan 37. The pick-up reels 38 are rotationally driven by motors 31, 32, 33, and 34, respectively. For example, for the drum 36 and the pick-up reel 38,
Rotation detectors 41 and 42 are supported, and rotation detection signals are manually input to the servo control section 30. The servo control unit 30 controls each of the motors 31 to 34 based on control information from the microcomputer 22, and controls the tape to be in normal forwarding, fast forwarding, rewinding, intermittent forwarding, stopped state, etc.

Next, the reproduction system of the above system will be explained.

During normal reproduction, signals detected by the rotary heads 40, 40 are supplied to the signal recording/reproducing section 24. Here, the error detection and correction section 25 performs error detection and correction. First, image data for one screen is written into the memory 16. The image data in the memory 16 is read out under the read control of the memory address generator 18, and is stored in the first image data as explained in FIG.
．． 2nd, 3rd. read out in the order of the fourth sub-screen signal,
Buffer amplifier 14. Frame memory 1 via bus 5
Written to 2. The image data written into the frame memory 12 is written as a complete one-screen signal in which sub-screen signals are combined, as shown in FIG. 2, under the address control of the frame memory address generator 11. The complete one-screen signal written to the frame memory 12 is transferred to the bus 5. The signal is supplied to a digital-to-analog converter 7 via a buffer amplifier 6 and converted into an analog signal. Then, the analog-converted signal is converted back to the original video signal by the modulator 8 and monitored.

The timing chart for the normal playback described above is as shown in FIG.

FIG. 6 (6a) is a writing period to the frame memory 16, during which sub-screen signals are written in sequence.

FIG. 6B shows a writing period to the frame memory 17, and sub-screen signals with the following contents are sequentially written to this memory 17 as well. The same figure (6C) shows frame memo 1.
It shows the period of data transfer from month 6 to the frame memory 12, and (6d) in the same figure shows the period of data transfer from the frame memory 17 to the frame memory 12. Further, (6e) in the same figure is a period in which one screen worth of image data transferred from the memory 16 to the frame memory 12 is displayed, and (6e) in the same figure is a period in which image data for one screen is transferred from the memory 17 to the frame memory 12.
This is the period during which one screen worth of image data transferred to 2 is displayed.

In this way, in this system, when reading signals from the tape are stored alternately in the memories 16 and 17 and displayed,
Image reproduction can be obtained by arranging and writing the signal array into the frame memory 12.

Next, the early draw mode will be explained.

In the early remote mode, the servo control unit 30 controls tape running so as to pick up the first sub-screen signals one after another as explained in FIG. FIG. 7 is a timing chart in the early draw mode.

FIG. 7 (7a) shows a period in which areas of the first sub-screen signal are successively reproduced. During this period, the tape speed is the same as during normal playback. However, as shown in FIG. 7(b), the second to fourth sub-screen signal areas are
Since there is no need for projection, the tape is run at twice the speed, for example. In this way, the tape is played in skips. (7C) in the figure is a period in which the first sub-screen signal is written into the memory 16, and (7d) in the figure is a period in which the next first sub-screen signal is written in the memory 17. And the same figure (7e
) is a period in which the contents of the memory 16 are transferred to the frame memory 12, and (7r) in the figure is a period in which the contents of the memory 16 are transferred to the frame memory 12. Furthermore, the same figure (7g
) is a period in which data transferred from the memory 16 is displayed, and (7e) in the figure is a period in which data transferred from the memory 17 is displayed. Here, when data is transferred from the memory 16 or 17 to the frame memory 12, the address control of the memory address generator 18 causes the frame memory 12 to receive the first sub-screen signal as shown in FIG. (2) is stored repeatedly several times, and if it is a normal screen, the signal (2) is stored and supplemented in the area where the signals (2), (2), and (3) are stored. In other words, this corresponds to expanding the signal of ■ by four times. The contents of this screen change each time the user passes the guard band 201 shown in FIG. Therefore, when the desired screen content is obtained, if the stop mode is set, the desired screen signal is stored in the frame memory 12, so it can be held for a long time.

In the above description, the display state of the first sub-screen is assumed to be displayed over the entire monitor screen. However, the display method is not limited to this, and various methods are possible.

FIG. 8 (8a) is an example in which, for example, four frames of first sub-screens with different contents are displayed on the same monitor screen. In this case, the data stored in the memory 16 or 17 can be expanded without being enlarged.
It is stored and displayed in each divided area. Also in the same figure (8b
) is an example in which the first sub-screen signal is further subsampled and reduced, and 16 first sub-screens with different contents are displayed on the same monitor screen 300. This display method is effective for viewing the entire contents of still images recorded on the tape. In addition, in the same figure (8C), the background screen is projected and a part of it shows the first screen.
This is an example in which a sub-screen of is displayed on the monitor screen 300. In this case, the first sub-screen signal written in the memory 16 or 17 is written as it is in a part of the frame memory 12, and each time the first sub-screen signal with the next content is reproduced. can be rewritten as This display method is effective when searching for an image with content related to the content displayed as a background image (for example, questions and answers).

In the above description, an example in which the present invention is applied to a digital tape recorder has been described. However, the present invention is not limited to this, and the recording medium or device as a whole may be applied to a floppy disk and a playback device for the same.

FIG. 9 shows the recording format of the floppy disk 400. In this case as well, similarly to the example explained in FIG. 4, track areas 41, 42, 43, and 44 in which the first to fourth sub-screen signals are recorded are provided between the guard bands 401 and 401.

[Effects of the Invention] As explained above, in this invention, by devising the distribution of image signals and the recording format, it is possible to sequentially obtain screen searches at high speed in the early search mode, and even if there is missing information, This is effectively compensated for and no noise is generated in the image.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of this invention, FIGS. 2 and 3 are explanatory diagrams for explaining the basic concept of this invention, and FIGS. 4 and 5 are details of this invention. FIG. 6 is an explanatory diagram shown for explaining the details. FIG. 7 is a timing chart shown to explain the present invention in detail, FIG. 8 is an explanatory diagram further shown to explain a display example according to the invention, and FIG. 9 is a timing chart shown to explain a display example according to the invention. It is a figure showing an example. 2... Analog digital converter, 3... Luminance color signal separation circuit, 4, 6, 13.14... Buffer amplifier,
7,...Digital-to-analog converter, 8...Modulator, 1
DESCRIPTION OF SYMBOLS 1... Frame memory address generation part, 12... Frame memory, 16.17... Memory, 18... Memory address generation part, 19... Header generation part, 21.
...Timing control unit, 22...Microcomputer, 23...Header detection unit, 24...Signal recording and reproducing unit, 25...Error detection and correction unit, 30...Servo control unit, 31, 32 , 33. 34... motor,
35... Supply reel, 36... Drum, 37.
...Capstan, 38...Tick-up reel, 4
0...Rotating head. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In an image recording and reproducing apparatus that forms a track on a recording medium and records an image signal or reproduces a recorded image signal from the track, a plurality of pixel signals obtained by subsampling one screen's worth of pixel signals in units of sub-screens is provided. 1. An image recording and reproducing apparatus comprising: means for dividing into sub-screen signals; and means for sequentially arranging these sub-screen signals into tracks.